Fundamental studies on the influence of wave loads on a trimaran’s cross-deck structure

For the design of trimaran structures, a lot of knowledge is necessary, and particularly it is important at an initial design stage to collect the qualitative knowledge under what wave conditions the stress concentration will occur. In the present paper, some fundamental numerical studies are carried out for the structural analysis of the trimaran using the whole ship model, particularly focusing on the strength of the cross deck. First, the hydrodynamic pressure for wave loads acting on the trimaran hulls is predicted based on the potential theory. These are input loads on the structure analysis of the trimaran, and the validity of the present approach is discussed with results of towing tank tests. Additionally, the load transfers should be done appropriately for the structure analysis. This is because the difference between the grid size of the hydrodynamic analysis and that of structure analysis, for example, finite-element (FE) analysis, may lead to a drop of computational accuracy. Next, the global strength of the target trimaran is discussed using the design loads by the rules. Finally, the local strength analysis using FE model is studied and the elastic behavior of the cross-deck structure is investigated to collect the useful properties for the cross-deck design.